1 files changed, 96 insertions, 0 deletions
diff --git a/toolkit/content/tests/widgets/test_popupreflows.xhtml b/toolkit/content/tests/widgets/test_popupreflows.xhtml
new file mode 100644
index 0000000000..c3f8068779
--- /dev/null
+++ b/toolkit/content/tests/widgets/test_popupreflows.xhtml
@@ -0,0 +1,96 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css" type="text/css"?>
+
+<window title="Popup Reflow Tests"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <panel id="testPanel"
+         type="arrow"
+         noautohide="true">
+  </panel>
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+<script>
+<![CDATA[
+let panel, anchor;
+
+// A reflow observer - it just remembers the stack trace of all sync reflows
+// done by the panel.
+let observer = {
+  reflows: [],
+  reflow (start, end) {
+    // Ignore reflows triggered by native code
+    // (Reflows from native code only have an empty stack after the first frame)
+    var path = (new Error().stack).split("\n").slice(1).join("");
+    if (path === "") {
+      return;
+    }
+
+    this.reflows.push(new Error().stack);
+  },
+
+  reflowInterruptible (start, end) {
+    // We're not interested in interruptible reflows.  Why, you ask?  Because
+    // we've simply cargo-culted this test from browser_tabopen_reflows.js!
+  },
+
+  QueryInterface: ChromeUtils.generateQI(["nsIReflowObserver",
+                                          "nsISupportsWeakReference"])
+};
+
+// A test utility that counts the reflows caused by a test function.  If the
+// count of reflows isn't what is expected, it causes a test failure and logs
+// the stack trace of all seen reflows.
+function countReflows(testfn, expected) {
+  return new Promise(resolve => {
+    observer.reflows = [];
+    let docShell = panel.ownerGlobal.docShell;
+    docShell.addWeakReflowObserver(observer);
+    testfn().then(() => {
+      docShell.removeWeakReflowObserver(observer);
+      SimpleTest.is(observer.reflows.length, expected, "correct number of reflows");
+      if (observer.reflows.length != expected) {
+        SimpleTest.info("stack traces of reflows:\n" + observer.reflows.join("\n") + "\n");
+      }
+      resolve();
+    });
+  });
+}
+
+function openPopup() {
+  return new Promise(resolve => {
+    panel.addEventListener("popupshown", function popupshown() {
+      resolve();
+    }, {once: true});
+    panel.openPopup(anchor, "before_start");
+  });
+}
+
+// ********************
+// The actual tests...
+// We only have one atm - simply open a popup.
+//
+function testSimplePanel() {
+  return openPopup();
+}
+
+// ********************
+// The test harness...
+//
+SimpleTest.waitForExplicitFinish();
+
+addEventListener("load", function() {
+  anchor = document.getElementById("anchor");
+  panel = document.getElementById("testPanel");
+
+  // and off we go...
+  countReflows(testSimplePanel, 0).then(SimpleTest.finish);
+});
+]]>
+</script>
+<body xmlns="http://www.w3.org/1999/xhtml">
+  <p>The anchor --&gt; <span id="anchor">v</span> &lt;--</p>
+</body>
+</window>